korean english


Home > 게시판 > 세미나

Oak Ridge National Laboratory의 최우석 박사님을 초빙하여 아래와 같이 특별세미나를 개최합니다.

학과 구성원 여러분의 많은 참석을 부탁 드립니다. 

         아             래  

     1. 일시: 2012년 10월 8일(월) 16:30 


     2. 장소: 물리학과 세미나실 (제1과학관 31355호실)


     3. 초청연사: 최   우   석  박사님 (Oak Ridge National Laboratory


     4. 제목: Versatile Spin State Transitions in Multivalent ACoOx Epitaxial Thin Films 


     5. 초록: Cobalt-based transition metal oxides exhibit a wide spectrum of physical properties owing to the multivalent nature of cobalt. Multiple d-electrons in cobalt ions are highly susceptible to a small deviation in the surrounding environment, such as strain-induced structural change or oxygen stoichiometry, which yields various electronic and magnetic ground states. In this talk, I will focus on our recent studies on ACoOx epitaxial thin films, which serve as an important model system in understanding the role of cobalt ion and related physical phenomena.
In the first part, strain-induced spin states in stoichiometric LaCoO3 thin films will be demonstrated [1]. I will show that the ferroelastic LaCoO3 thin film adopts epitaxial strain in a unique way, exhibiting an unconventional strain relaxation mechanism. This strain relaxation behavior further resulted in modification of cobalt spin states, shedding light onto the mysterious ferromagnetic ground state of LaCoO3 thin films. In the second part of the talk, topotactic phase transformation and subsequent physical property changes in SrCoOx epitaxial thin films will be discussed [2]. In particular, the two end members of SrCoOx: SrCo3+O2.5 and SrCo4+O3.0 showed drastically different electronic and magnetic ground states. Moreover, owing to the multivalent nature of cobalt, these two considerably different phases could be reversibly transformed from one to the other at relatively low temperatures. The simple and fast topotactic transformation turned out to be useful for many technological applications utilizing oxygen ion transport of cobalt-based transition metal oxides, including solid oxide fuel cells and electrochemical sensors.


[1] W. S. Choi, J.-H. Kwon, H. Jeen, J. E. Hamann-Borrero, A. Radi, S. Macke, R. Sutarto, F. He, G. A. Sawatzky, V. Hinkov, M. Kim, and H. N. Lee, Nano Lett. published online at http://pubs.acs.org/doi/abs/10.1021/nl302562f (2012).
[2] H. Jeen, W. S. Choi, M. D. Biegalski, I. C. Tung, J. W. Freeland, D. Shin, H. Ohta, M. F. Chisholm, & H.  N. Lee, under review.

번호 제목 날짜 조회 수
공지 <12/8(Thu.) 11:00am>노벨상 소개 강연 - 2016년 노벨 물리학상: 위상 응집 물리의 탄생 2016.11.28 1079697
527 <9/24(수)> Design Principles of Cellular Networks 2014.09.18 66944
526 <7/18(Mon.) 14:00> GEANT4 Particle Physics Simulation Software: A Brief Overview From a User’s Perspective 2016.07.15 66959
525 <9/11(목)> The effects of dark matter elastic scattering on the cosmological signals 2014.09.01 66983
524 <10/1(수)> 초전도 양자컴퓨터 - Superconducting qubit and circuit QED 2014.09.26 67087
523 <March.24(Thu) 14:00> A new boson and muon g-2 2016.03.17 67093
522 <4/3> 내 안의 파장을 바꿔라! 2013.03.29 67199
521 <12/21(금)> Generic quantum spin ice 2012.12.03 67389
520 <3/22> 석학초청 특별강연 – Pyeongyang Advances Its Nuclear Program 2012.03.07 67406
519 <12/11> Is Nature Natural? 2013.12.05 67470
518 <May.1(Wed.)> Introduction of AMS Application 2019.04.24 67519
517 <11/14> Next Generation LED 2012.11.08 67813
516 <6/24(Fri.) 1:30pm>Emergent geometry from field theory: Wilson's renormalization group revisited 2016.06.20 68042
515 <10/24> Dung-hai Lee 교수와의 간담회 2012.10.23 68251
514 <3/13> Quantum computing using solid state nano-devices 2013.03.08 68300
513 <8/29(토)> 세미나 개최 안내 2015.09.01 68309
512 <6/10(수) 오후4:30분> Closing in on the Axion Dark Matter hypothesis 2015.06.03 68380
511 <3/14> Proto-neutron star 2012.03.08 68408
510 <Oct.2(Wed.)> Fundamental physics with high-energy atmospheric and cosmic neutrinos today and in the future 2019.09.26 68596
509 <May. 11(Wed.) 4:30 PM> In-situ x-ray studies of functional oxides for energy systems 2016.05.23 68601
508 <12/10(수)> Magnetic Resonance Imaging: What is relevant to physics 2014.12.04 68829